Materials positioning fork



Jan. 31, 1967 L. L. HEIKKINEN 3,301,587

MATERIALS POSITIONING FORK Filed March 1, 1965 '7 Sheets-Sheet l INVENTOR LEO L Hf/K/(IMEN Wag/av 7 Sheets-Sheet 2 Filed March 1, 1965 INVENTOR L.

Jan. 31, 1967 I... L.. HEIKKINEN 3,301,587

MATERIALS POS ITIONING FORK Filed March 1, 1965 7 Sheets-Sheet 5 INVENTOR LEO L. HE/KK/NE/V Jan. 31, 1%?

Filed March 1, 1965 L. 1. HElKKlNEN MATERIALS POS ITIONING FORK 7 Sheets-Sheet 4 INVENTOR LEO L. HE/KK/NE/V ATTQKWEY Jan. 31, 1967 HElKKiNEN 7 3,301,587

MATERIALS POSITIONING FORK INVENTOR LEO L. HE/K/(l/VEN ATTEY Jain 31; B67 I... L... HEIKKINEN L MATERIALS POSITIONING FORK Filed March 1, 1965 7 Sheets-Sheet INVENTOR LEO L. HE/K/(l/VEA/ Jan. 31, 1967 L. L.. HEIKKENEN 3,301,587

MATERIALS POSITIONING FORK Filed March 1, 1965 '7 Sheets-Sheet 7 INVENTOR L. HEiWK NE/V BY mm M available.

United States Patent 3,391,587 MATERIALS POSITIONING FORK Leo L. Heikkinen, Prentice, Wis, assignor to Prentice Hydraulics, Inc., Prentice, Wis. Filed Mar. 1, 1965, Set. N0. 436,139 12 Claims. (Cl. 294-67) This invention relates gene-rally to the field of materials handling devices and particularly is directed toward a fork lifting device adaptable for use with a boom type crane in the lifting and handling of flat, rigid building materials, such as sheets of wallboard and the like.

This is a continuation-in-part application of my copending application Serial No. 399,986, filed September 29, 1964, titled Materials Positioning Fork, now abandoned.

Heretofore the standard way of handling materials of this nature at building construction sites was to use the standard fork lift truck or the like for removing the stacks of material from the bed of a delivery truck where they had been conveniently stacked on pallets. The tractor type of fork lift conveyor would carry the material from the truck closer to the construction site at the ground level of the construction site. As each individual sheet of material was needed for installation it was hand carried from the ground level up to the upper level for use. Mechanical devices were sometimes used for raising stacks of this material up to the desired building level and then the individual sheets were removed from the stack as needed. The principal reason for handling this type of material in this manner has been the limited maneuverability of the lifting devices which have been It has not been possible to position stacks of the material, as they are being lifted, so that they can be swung through a convenient opening such as a window or a door at the upper levels of buildings under construction. Mate-rials of this nature are generally of the finishing type and after the rough construction is in,

including roughed-in walls and window and door frames,

it is necessary to bring in the stacks of finishing material, such as wallboard and the like, through limited openings. Mechanical lifting devices must be highly maneuverable in order to position the material while lifting it so that it can be conveniently broughtinto the building through these limited openings.

It is a primary object of this invention to provide a lifting and handling device for fiat, rigid building materials with improved maneuverability.

A further object of this invention is to achieve the immediately foregoing object wherein the greater maneuverability is selectively controllable by an operator.

-A specific object of this invention is to provide a fork lift for rigid, flat building materials which is attachable to a boom type crane capable of being selectively maneuverable to a multitude of positions without undesirable swaying.

A further object of this invention is to provide a lifting and handling device for rigid, flat building material for facilitating the loading and unloading of delivery trucks.

Still another object of this invention is to provide mechanical means for unloading rigid, flat building material from delivery trucks and lifting it into a position for convenient handling while minimizing swaying of the unloading device.

Yet another object of this invention is to provide a device which reduces the amount of manual lifting and carrying of heavy, flat, rigid building materials which has been necessary heretofore.

The preferred embodiment of this invention essentially comprises a fork lift having generally flat forward extending tines for lifting and holding the rigid flat building material and which is pivotally connected to one end of an L-shaped arm. A hydraulic driven piston is connected between the arm and the fork lift to cause the latter to swing about its pivotal connection so that the tines can be selectively positioned anywhere between horizontal and vertical orientation. The other end of the arm is connected to the end of any well known boomtype crane by linkages which are interrelated and interconnected in a manner to permit the arm, along with the attached fork lift, to move or rotate about three mutually perpendicular axes, thereby permitting virtually unlimited maneuverability of the fork lift with respect to the crane. crane operator to selectively position the fork lift as he desires and braking features are incorporated to minimize undue swaying of the apparatus during normal use.

These and other features and advantages of this invention will become apparent in the course of the following detailed description with reference to the accompanying drawings in which:

FIG. 1 is a perspective view showing the over-all construction of the preferred embodiment of this invention;

FIG. 2 is another view of the device illustrated in FIG. 1, more clearly illustrating the device in use for holding sheets of flat rigid material;

FIG. 3 illustrates the relative motion ofthe fork lift and its engaging arm when used to lift the materials from the bed of a truck;

FIGS. 4, 5, 6, 7 and 8 show in detail the construction of the linkages between the crane and arm which provide the great amount of maneuverability for the device, and

FIG. 9 is a perspective view showing the overall construction of another embodiment of this invention.

A general overall perspective View of the construction of a preferred embodiment of this invention is shown in FIG. 1. A generally U-shaped fork lift 10 is constructed from suitable members which are welded or otherwise permanently joined together in the well known fashion and includes a pair of forward extending elongated tines 11 and 12. At the front edges of the tines are cylindrical rollers 13 which facilitate slipping the tines under the stack of material, such as wallboard and the like, while protecting against the tines scratching or otherwise damaging the material being handled. At the base of the tines there is mounted, in any suitable manner, a padding of material 14 which also prevents damage to the material being handled and facilitates removal of the material after it has been hoisted to its point of delivery. Preferably this padding is made of a tough material such as Teflon, which will withstand rugged use but will allow the sheets of material to be slipped out of the fork lift easily. At its other extremity the fork lift 10 is pivotally attached by a pair of pivot pins 15 to one end of an L-shaped arm 16. Connected between the base of the fork lift 10 and the arm 16 is a hydraulic cylinder 17. At its opposite end the L-shaped arm 16 is pivotally at tached by additional pivot pins 18 to the vertical side members of a bracket assembly 19 and from there through appropriate linkages, which will be subsequently described in greater detail, to the end of a boom type hydraulic crane 20. Hydraulic line 21 runs from the crane to the hydraulic piston 17 for controlling the latter and hydraulic lines 22, 23 and 24 provide the means for controlling the operation of the linkages to the crane to selectively control maneuvering of the fork life. A hydraulic motor 30 is mounted vertically in the bracket assembly 19 and can be driven in a suitable manner to cause the bracket assembly with the connected arm 16 and the fork lift 10 to rotate about a vertical axis. Swivel couplings 45 Suitable controls permit the remotely located and 46, which are suitably mounted, permit controlled motion of the bracket assembly 19, arm 16 and fork lift about a pair of horizontal, mutually perpendicular axes thereby providing the desired maneuverability with respect to the crane 20.

FIG. 2 shows the relative positions of the elements of the fork lift 10 and the L-shaped arm 16 after a stack of sheets of rigid building material 25, shown in shadow line and which might be wallboard for example, has been grasped and lifted. As is more clearly shown in FIG. 2, the piston chamber 17a of the hydraulic cylinder 17 is pivotally attached by pin 26 to the base of the fork lift 10 at one end. At the opposite end, the piston 17b is pivotally attached by pin 27 to the arm 16. Progressive position of the fork lift 10 from an initial horizontal position, as shown in FIG. 1, to a final vertical position, as illustrated in FIG. 2, are shown in FIG. 3. The horizontally disposed tines 11 and 12 are slipped under the stack of material to be lifted, which is previously stacked on a pallet in the usual manner, and the remotely located operator by appropriately controlling the passage of hydnaulic fluid through hydraulic line 21, operates the hydraulic cylinder 17 to cause the piston 17b to begin its withdrawal or pushing stroke. The forces applied thereby to the arm 16 and the fork lift 10 cause the latter two to pivot with respect to their pivotal connections so that when the cylinder piston 17b is at its furthest extended position, the fork lift is in a substantially vertical position. Obviously the operator can set the position of the fork lift 10 as he desires to any position between the horizontal and the vertical extremes. With the fork lift positioned by the operator as described, via the linkages between the arm 16 and the crank 20, the :fork lift can be manipulated about three mutually perpendicular axes so that the material being lifted can be maneuvered to an infinite number of positions as suitably desired for loading and unloading.

The hydraulic motor 30 is mounted with its drive shaft in a vertical position in bracket assembly 19. Hydraulic fluid is applied to control operation of motor 30 through hydraulic lines 23 and 24. Hydraulic motors for the use contemplated are well known in the art and detailed description of the construction and operation of the motor is not considered necessary since those of ordinary skill in the field of hydraulically controlled lifting devices will be able to select the proper hydraulic motor for the use contemplated after reading the detailed description of the invention. Typically, a hydraulic motor used in the construction of the embodiment of this invention as described herein is an Orbit (trademark) motor manufactured and sold by the Char-Lynn Company of Minneapolis, Minnesota. Suffice it to point out that the shaft of this motor can be rotated continuously in either direction through 360 degrees. Obviously, for use in the present invention the motor shaft generally need not be driven more than 360 degrees in either direction.

Swivel couplings 45 and 46 provide the freedom of motion about two mutually perpendicular axes, both of which are perpendicular to the axis of rotation of the hydraulic motor. Pivot pins 47 and 48 respectively couple swivels 45 and 46 to the sidewalls of the end of the crane 20 and to the brackets 44.

Referring now to the sectional view shown in FIG. 4, the outer frame of the vertically oriented hydraulic motor 30 is attached, such as by bolts as illustrated, to a torque plate 31 which in turn is mounted on a supporting plate 32 forming part of the construction of the bracket assembly 19. This ring-like, horizontal supporting plate 32 is integral with or is otherwise affixed to the vertically disposed side walls of the bracket assembly 19. The shaft 30a of the hydraulic motor 30 extends above the torque plate 31 and is splined to a sleeve 33 with a key 34. Through this sleeve 33, a cylindrical annular coupling 35 and another key 36, the shaft 30a of the hydraulic motor 30 is attached to a small diameter countershaft 37. The larger diameter main shaft or rod 38 which is an integral extension of shaft 37, extends upward through a cylindrical bearing 39 held in the bracket assembly 19 by the inward sloping supports or webs 40 which extend inward and upward from the vertical side walls of the bracket assembly 19. In the well known manner, suitable thrust washers 41 and a thrust collar 42 provide support for the shaft 38 at each end of the bearing 39. At its upper extremity the shaft 38 is permanently attached, as by welding, to a horizontally disposed disc-like supporting plate 43. Plate 43 constitutes the base member of another bracket support asembly containing a pair of vertically disposed side walls 44, more clearly shown in FIGS. 5 and 6. Projecting downward from the plate 43 is a dog 63 to provide a mechanically fixed stop. A floating stop plate 64 includes circumferential section 64a which has its outer periphery at a radius substantially longer than that of the rest of the member 64, thereby defining a pair of shoulders 64b and 64c. When the floating stop 64 is rotated about its vertical axis, which passes through the central aperture, a predetermined amount of one of the shoulders 64b or 640, will come into contact with the fixed stop, dog 63, thereby terminating rotation of the floating stop. An car 65 similar to dog 63, extends downward from the floating stop 64. This ear, when the floating stop is rotated about the vertical axis, butts up against a protrusion 66 which extends outward from the bearing support 40. The operative relationship of these various component parts can best be shown by considering the operation of the device as it is rotated by the hydraulic motor.

The operator, who is remotely located, by manually operable controls, not shown, causes the hydraulic fluid to be admitted through the hydraulic lines 23 and 24 to the motor as desired to cause either clockwise or counterclockwise rotation about the vertical axis. Assuming clockwise rotation (looking upward), since shaft 30a of the hydraulic motor 30 is locked to the fixed shaft 38 through coupling 35 and the intermediate shaft 37, the frame (or what is normally considered the stator) of the motor rotates about the vertical axis with respect to shaft 38. The bracket assembly 19, to which the motor frame is attached, and the remainder of the apparatus coupled thereto including the arm 16 and the fork lift 10, rotate about the vertical axis as defined by the longitudinal axis of the shaft 38 along with the bracket assembly 19. After rotation of a determinable number of degrees, the protrusion 66 comes into contact with the ear 65 on the floating stop 64 causing the latter, in turn, to begin rotating about the same vertical axis. This will continue until the shoulder 64c comes into contact with the front edge of dog 63 which terminates any further rotation in the clockwise direction. However, the operator can now control the feed of the hydraulic fluid through the hydraulic lines 23 and 24 to the motor 30 to cause the latter to reverse the direction of rotation. The attached bracket assembly 19 along with the rest of the apparatus coupled thereto, including the fork lift 10, will rotate counter-clockwise until shoulder 64b makes contact with the other edge of fixed stop 63, in the same manner as described above for clockwise rotation. Through the arrangement of the stops as described, there is provided freedom of rotation somewhat greater than 360 degrees to achieve maneuverability of the fork lift of a much greater flexibility than heretofore experienced. As a practical matter, the reason for limiting the rotation of the fork lift is to prevent the hydraulic lines from becoming entangled.

The linkages between the bracket assembly 44 and the crane 20, including the swivel couplings 45 and 46, will now be described in detail with particular reference to FIGS. 7 and 8. Pin 47 is secured to the end of the crane 20 by a nut 49. Enclosing most of the length of pin 47 is a cylinder '50 having a pair of end plates 51 and 52 which are slidalble in a piston-like manner longitudinally ofthepin'47- These movable end plates are keyed to the cylinder by dowels 53. Pin 47 contains a passageway 54 which is in communication with the hydraulic line 22. The space formed between the surface of pin 47, the inner surface of the cylinder 50 and the inner ends of the end plates 51 and 52 define a fluid containing chamber 55. Disc-like brake linings 56 are located between the outer end surfaces of end plates 51 and 52 and the inner surfaces of the sidewalls at the end of the crane 20. Increasing the fluid pressure in the hydraulic line 22 and through the passageway 54 into chamber 55 forces the end plates 51 and 52 to slide outward along the longitudinal axis of the pin 47 so that they bear down upon the brake linings 56 to impede or completely stop the rotation of the cylinder 50 about the pivot pin 47. When it is desired to permit greater freedom of rotation, hydraulic pressure in the line and the chamber is reduced thereby reducing the braking friction between the cylinder 50 and the crane 20.

As most clearly shown in FIG. 8, an outer cylindrical member 57 of swivel 46- is integrally attached and permanently affixed to the cylindrical member 50 in swivel 45, such as by welding as illustrated at 53, and encloses pin or bolt 48 along a substantial section of its length. Swivel 46 may be constructed similar to swivel 45 with hydraulic braking control as previously described for selectively setting the braking friction as desired, or it may be constructed with a mechanically adjustable preset brake, as illustrated in FIG. 5. Increased pressure on bolt 48 caused by tightening the securing nut, is applied through the end plate discs 59 and springs 60 to disc-type brake linings 61 to increase friction on the ends of the cylindrical member 57. This increases the braking action and reduces the rotational freedom that bracket 44 has about the longitudinal axis of the bolt 48. The degree of braking action is generally set before the apparatus is put into use. This is generally referred to as a continuous drag device and its principal function is to limit undue swinging and swaying of the fork lift as it is being used to hoist the material into position while still allowing some pivoting freedom. Referring back to FIGS. 1, 2 and 3, it can be seen that the swivel 46 and the entire mechanism below which depends therefrom can swing about the axis defined by the longitudinal axis of pivot pin 47 which passes through the center of the swivel 45. Further, it can be seen that the bracket 44 as well as the mechanism attached thereto and depending therefrom can swing about the axis defined by the longitudinal axis of bolt 48 which passes through the center of the swivel 46. This unique combination of swivel couplings constructed in the manner described allows freedom of motion of the lifting fork about two mutually perpendicular axes. When combined, in turn, with the mechanism for driving the fork about a third axis in the manner previously described, the improved maneuverability achieved bythis invention becomes apparent.

The construction of another embodiment of this invention is illustrated in FIG. 9. The principal feature of this latter embodiment is that higher stacks of material can be grasped and lifted by the fork lift. In this embodiment the swivel mechanism at the end of the crane is coupled to the fork lift by two elongated rigid arms 70 and 71 which are pivotally joined together at one end 72. The other end of arm 70 is pivotally connected to the shaft 18 and the other end of the arm 71 is pivotally connected at 73 to the back of the tines of the fork A pair of strengthening struts 74 are similarly pivotally connected between the general area where the two arms join at 72 at the back of tines of the fork lift 10. A hydraulic cylinder 75, which serves the same function as the hydraulic cylinder 17 contained in the embodiment illustrated in FIG. 1, is in like manner connected between the one end of arm 70 and the rear of the fork lift 10. A suitable fluid coupling line 76 is attached to the hydraulic cylinder 75 for remote control of said cylinder.

This provides the means for remotely positioning the fork lift between the horizontal and vertical orientation as desired for lifting and carrying.

As an added feature in the embodiment shown in FIG. 9, the fork lift tines 77 and 78 are detachably locked onto the supporting back brace 79 by pins such as 80 which are removably inserted into spaced-apart slots 81. This provides a convenient means for spacing the tines 77 and 78 according to the width of the load being carried. The pins 80 are lifted out of the slots and the tines positioned laterally along the back brace 79 as desired. Then the pins are reinserted to securely lock the tines in position.

I claim:

1. A materials handling device, comprising: a fork lift for handling generally flat rigid material; a generally L-shaped arm pivotally attached at one of its ends to one end of said fork lift; a hydraulically actuable piston operatively connected between said arm and said fork for swinging said fork about said pivot attachment to lift the material being handled; and means attached to the other end of said arm for coupling said arm to a boom type crane for operative engagement therewith.

2. The invention as described in claim 1 wherein said means for coupling the arm to the boom type crane, includes: a first horizontally disposed cylindrical swivel member attached to the end of the crane between a first pair of parallel bracket plates, said first swivel member being rotatable about its axis; a second cylindrical swivel member fixedly attached directly to said first swivel member between its ends, the axis of the second swivel member being perpendicular to that of the first swivel member; a second pair of parallel bracket plates extending down from the ends of said second swivel member and rotatable about the axis of said second swivel member; a base plate fixedly attached to the second pair of bracket plates below said second swivel member; a shaft extending downward from said base plate; a third pair of bracket plates rotat-ably mounted to said shaft; a cylindrical hydraulically-actuated drive means mounted concentric with said shaft for rotating said third pair of bracket plates about said shaft; and means for attaching said third bracket plates to said other end of said L-shaped arm.

3. The apparatus as described in claim 2 further ineluding hydraulically-actuated braking means contained in at least one of said swivel means for controlling the freedom of rotation of the swivel.

4. For use in a materials handling device: a fork lift having elongated tines for lifting and holding flat, rigid material; a generally L-shaped arm pivotally attached at one end to said fork lift at a point remote from said tines; hydraulically actuable piston means connected between said fork lift and said arm for swinging said tines about said pviotal attachment between horizontal and vertical positions; a horizontally disposed rod means passing between and through the side plates of a bracket means for pivotally connecting the other end of said arm to said bracket means; means for rotatably coupling said bracket means to a vertically disposed shaft; and hydraulically actuated drive means mounted concentric with said shaft for driving said bracket means rotationally about the axis of said shaft.

5. For coupling a fork lift to a loading and unload ing boom: a first cylindrical swivel attached to the end of the boom for providing rotational movement about a first axis; a second cylindrical swivel fixedly attached directly to said first swivel with its axis perpendicular to said first axis for providing rotational movement about its axis; a vertical shaft coupled to said second swivel for providing rotational movement about a third axis which is mutually perpendicular with the first and second mentioned axes; means for coup-ling a fork lift to said shaft; means for selectively moving said swivels and said shaft about the respective axes for selectively positioning said fork lift; and means contained in said swivels for selectively braking the movements about the respective axes.

6. The invention as in claim 4 further including a pair of cylindrical swivel means fixedly attached to one another with their axes perpendicular for coupling said shaft to the end of a boom type crane.

7. In a material handling device, apparatus for coupling a lifting fork to a loading and unloading boom, comprising: a first horizontally disposed cylindrical swivel member attached to the end of the boom between a first pair of parallel bracket plates, said first swivel member being rotatable about its axis; a second cylindrical swivel member fixedly attached directly to said first swivel member between its ends, the axis of the second swivel member being perpendicular to that of the first swivel member; a second pair of parallel bracket plates extending down from the ends of said second swivel member and rotatable about the axis of said second swivel member; a base plate fixedly attached to the second pair of bracket plates below said second swivel member; a shaft extending downward from said base plate; a third pair of bracket plates rotatably mounted to said shaft; cylindrical hydraulically-actuated drive means mounted concentric with said shaft for rotating said third pair of bracket plates about said shaft; and an L-shaped arm pivotally attached between said third bracket plates and a lifting fork.

8. A coupling apparatus as in claim 7 wherein said L-shaped arm is pivotally attached at one end to said third bracket plates and at the other end to said lifting fork.

9. The coupling apparatus as in claim 7 further including: hydraulically actuated means contained in at 8 least one of said swivel members for controllably braking the rotation of said swivel member about its axis.

10. The coupling apparatus as in claim 7 further including: means in said swivel members for braking the rotation of said swivel members about their respective axes.

11. The invention as in claim 3 wherein said braking means comprises: a disc-like plate at each end of the swivel means movable along the axis of the swivel means; a fluid-containing chamber within the swivel means between said end plates; and means connected to said chamber for selectively increasing or decreasing the fluid pressure in the chamber to move said end plates correspondin-gly outward or inward to correspondingly increase or decrease the braking friction on the swivel means.

12. The invention as in claim 9 wherein said braking means comprises: a disc-like end plate at an end of the swivel means, said end plate movable lengthwise of the swivel; said end plate defining one end of a fluid-containing chamber in the swivel means; and means for selectively controlling the fluid pressure in said chamber for controllably changing the frictional force between said end plate and the swivel means bracket.

References Cited by the Examiner UNITED STATES PATENTS 9/1958 Brennan 2l4l47 1/1959 Shook 294-l47 

1. A MATERIALS HANDLING DEVICE, COMPRISING: A FORK LIFT FOR HANDLING GENERALLY FLAT RIGID MATERIAL; A GENERALLY L-SHAPED ARM PIVOTALLY ATTACHED AT ONE OF ITS ENDS TO ONE END OF SAID FORK LIFT; A HYDRAULICALLY ACTUABLE PISTON OPERATIVELY CONNECTED BETWEEN SAID ARM AND SAID FORK FOR SWINGING SAID FORK ABOUT SAID PIVOT ATTACHMENT TO LIFT THE MATERIAL BEING HANDLED; AND MEANS ATTACHED TO THE OTHER END OF SAID ARM FOR COUPLING SAID ARM TO A BOOM TYPE CRANE FOR OPERATIVE ENGAGEMENT THEREWITH. 